Google has updated its privacy policy - in fact, it has consolidated a mess of over 70 different privacy policies each covering an individual service into one, simpler policy. You'll now be treated as a single account, and data will be shared between Google services to make search results and ads more personalised (I assumed they already did that - makes sense).

What is happening is that Google+ links are being prioritised over, say, Twitter links even when the Twitter link is full of data and the Google+ plus link is to an empty space, and that this is being done when Google has access to both sources of data. This is not happening because Google is being 'shut out' of any data source, Google has the data that shows that the Twitter link is the richer source on the topic being searched but it chooses to downplay it below Google's own but inferior data sources.

I require proof of your theory. Twitter publically shut off their fire hose to Google and then moved to JavaScript based URLs… so how does Google get this data now?

If you don’t recall so far back, Google often featured Twitter URLs in results until that change.